Cobalt extraction and recycling from permanent magnets

ABSTRACT

Systems and methods for recovering cobalt and other valuable metals from cobalt permanent magnets of various compositions, such as samarium cobalt magnets, are presented herein. In one embodiment, a method includes converting the permanent magnet material to a higher surface area form, such as a powder. The method also includes treating the converted permanent magnet material with an aqueous solution of ammonium carbonate to form a mixture (e.g., a slurry) that includes dissolved cobalt. In some embodiments, the method includes exposing the mixture to an oxidant to oxidize metallic constituents and form soluble species. The method also includes filtering the mixture to yield a filtrate and electroplating the cobalt onto a cathode from the filtrate.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application claims the benefit of U.S. Provisional PatentApplication No. 63/165,467 (entitled “Cobalt Extraction and Recyclingfrom Permanent Magnets” and filed on Mar. 24, 2021), the contents ofwhich are hereby incorporated by reference.

GOVERNMENT SUPPORT STATEMENT

This invention was made with government support under U.S. Department ofEnergy contract no. DE-SC0020853. The government has certain rights inthis invention.

BACKGROUND

Cobalt is commonly used to produce samarium cobalt permanent magnets,lithium-ion battery cathodes, catalysts, and high-grade metal alloys.These important strategic uses for cobalt combined with its limiteddomestic production have led the U.S. Department of the Interior to listit as a critical material. Furthermore, approximately 70% of the world'ssupply of mined cobalt comes from the Democratic Republic of the Congowhere concerns over environmental degradation and child labor have ledsome large cobalt consumers to selectively purchase cobalt fromsuppliers who meet certain standards, providing an economic incentive todevelop alternate cobalt sources. Recycling has already been shown to bea viable cobalt source with an estimated 29% of cobalt consumption inthe United States coming from recycled scrap. One source for recycledcobalt is from samarium cobalt (SmCo) magnets, which are commonly usedas high-strength permanent magnets in applications where thermalstability and corrosion resistance is required. These magnets have beenproduced with two nominal formulas: SmCo₅ and Sm₂Co₁₇ with the secondgeneration Sm₂Co₁₇ formulation being more common and representing thebulk of the market. In practice, Sm₂Co₁₇ magnets contain additionaltransition metals including iron, copper, and zirconium which makestheir recovery and reuse challenging and expensive. However, as thesemagnets typically contain about 50% cobalt by weight, they are adesirable secondary source for cobalt.

Several processes have been developed for the recovery of cobalt fromsecondary sources. One such process was developed by the U.S. Bureau ofMines using a double-membrane electrolytic cell to electro-refine alloyscrap into high-purity cobalt. This process uses an electrolyticdissolution step, multiple purification steps including cementation andmultiple solvent extraction steps to produce a purified cobalt solutionprior to electrodeposition of the cobalt. This process can produce highpurity cobalt but requires many processing steps that increase theoverall cost if additional valuable metals are not also purified andrecovered, e.g., nickel in this approach.

Direct recycling of samarium cobalt magnets is possible through aprocess termed hydrogen disproportionation desorption recombination(HDDR). First, magnet scrap is converted into a powder through reactionwith hydrogen at high pressure or temperature causing dissociation ofthe material to elemental forms or hydrides. Next, the hydrogen isdesorbed by heating in vacuum leading to recombination of the material,which can then be sintered or plastic bonded to form a new magnet.However, this process requires high-pressure or high-temperatureconditions to fully dissociate the material and, as magnet manufacturingis not the major use of cobalt, is limited to the production ofadditional samarium cobalt magnets.

Alternate approaches include acidic digestion and solvent extractionusing various surfactants and complexing ligands. However, theseapproaches all suffer from various drawbacks. Acidic digestion solutionsare not recyclable and require significant consumption of base toneutralize the acid, generating a significant amount of waste in theprocess. Solvent extraction often requires many stages to achievesufficient purity resulting in complex and costly systems.

SUMMARY

Systems and methods herein provide for recovering cobalt (and/or othermetals) from a permanent magnet material having variable composition,such as samarium cobalt magnets. In one embodiment, a method includesconverting the permanent magnet material to a higher surface area form,such as a powder. The method also includes treating the convertedpermanent magnet material with an aqueous solution of ammonium carbonateto form a mixture (e.g., a slurry) that includes dissolved cobalt. Insome embodiments, the method includes exposing the mixture to an oxidantto oxidize metallic constituents and form soluble species. The methodalso includes filtering the mixture to yield a filtrate, andelectroplating the cobalt and/or other metals, such as copper or nickel,onto a cathode from the filtrate.

For example, in some embodiments, filtering the slurry may removeprecipitated compounds and form a filtrate. From there, the filtrate maybe placed in an electrochemical reactor which selectively reduceselements by applying a potential across two electrodes to plate othermetal contaminants or coproducts (e.g. copper). Then, the electrode andplated metal (e.g., on the cathode) from solution can be removed. Thisprocess may be repeated at increasing electric potential to sequentiallyplate additional metals, to remove the plated cobalt metal from theelectrode, and to rinse the cobalt metal product. The extractionsolution, depleted of cobalt and any coproducts, can be directly reusedto extract more cobalt or coproducts from additional cobalt-containingmaterial.

The ammonium carbonate process is a recyclable solution that eliminateswaste generated from neutralizing acids, and avoids the complexity andcost of the many stages used in traditional solvent extraction methods.For example, reagents such as ammonium carbonate, oxygen, and water canbe recycled in a process that uses moderate temperatures, pressures, andenvironmentally benign chemicals.

In some embodiments, the permanent magnet material comprises samariumcobalt magnets (e.g., either partially or completely oxidized samariumcobalt magnets). In some embodiments, the method includes deriving thepermanent magnet material from magnet manufacturing wastes.

In some embodiments, electroplating the cobalt includes recovering atleast one of copper or nickel from the electroplating as a co-product.In some embodiments, converting the permanent magnet material to ahigher surface area form includes at least one of grinding or millingthe permanent magnet material.

In some embodiments, the method also includes heating the mixture in atleast one of air, an inert atmosphere, or hydrogen to temperatures up to1500° C. The method may also include demagnetizing the mixture using anexternally applied magnetic field or a mechanical shock treatment. Themethod may also include adjusting an oxidation state of the mixtureprior to extraction with a chemical oxidant, a reductant, or anelectrochemical method that employs an electric current to transferelectrons between materials.

In some embodiments, the aqueous solution of ammonium carbonatecomprises ammonium carbonate and ammonia, and the method also includesrecycling the aqueous solution of ammonium carbonate after use. Forexample, the aqueous solution of ammonium carbonate may be thermallytreated after use to convert the used ammonium carbonate solution intoammonia and carbon dioxide.

In some embodiments, treating the converted permanent magnet materialwith an aqueous solution of ammonium carbonate includes adding at leastone of oxygen gas, air, hydrogen peroxide, a chemical oxidant, hydrogengas, or a chemical reductant. In some embodiments, the method alsoincludes applying an electrical potential to a slurry containingalkaline carbonates and the permanent magnet material to increase adissolution rate. In some embodiments, the method also includes heatingthe aqueous solution of ammonium carbonate to a temperature between 0°C. and 100° C. at a pressure above 1 bar.

In some embodiments, one or more of said converting, treating theconverted permanent magnet material, filtering, and treating thefiltrate are performed in a container constructed of at least one ofstainless steel, glass, polytetrafluoroethylene, fiberglass-reinforcedplastic, corrosion resistant alloy, or a corrosion barrier. In someembodiments, the method also includes adding reagents to the mixture toslow hydrogen evolution at the cathode or to increase a rate of oxygenevolution at an anode.

In some embodiments, additives may improve the quality of theelectroplating. An electroplating reactor may include at least one of asingle chamber or multiple chambers separated by an ionically conductivemembrane. Two or more electrodes may be used in the electroplating(e.g., for reduction, oxidation, and/or reference). And, solids obtainedby filtration may be recovered as a byproduct for additional processingor recycled use.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an exemplary system for recovering cobaltand/or other metals from permanent samarium cobalt magnets.

FIG. 2 is a flowchart of an exemplary process of the system of FIG. 1.

FIG. 3 is a block diagram of an exemplary computing system in which acomputer readable medium provides instructions for performing methodsherein.

DETAILED DESCRIPTION

The figures and the following description illustrate specific exemplaryembodiments of the invention. It will thus be appreciated that thoseskilled in the art will be able to devise various arrangements that,although not explicitly described or shown herein, embody the principlesof the invention and are included within the scope of the invention.Furthermore, any examples described herein are intended to aid inunderstanding the principles of the invention and are to be construed asbeing without limitation to such specifically recited examples andconditions. As a result, the invention is not limited to the specificembodiments or examples described below.

Exemplary Cobalt Extraction and Recycling from Permanent Magnets (CERPM)processes are disclosed herein and are operable to recover cobalt andother valuable metal elements from samarium cobalt magnets.

FIG. 1 is a block diagram of an exemplary system 10 for recoveringcobalt and/or other metals from permanent samarium cobalt magnets. Inthis embodiment, the system 10 includes a milling/grinding module 12that is operable to convert a samarium cobalt magnet feed into a highersurface area form, such as powder. Generally, the samarium cobalt magnetfeed is obtained from recycling samarium cobalt magnets and/or fromwaste associated with manufacturing samarium cobalt magnets. Aftermilling/grinding the samarium cobalt magnet feed, the samarium cobaltmagnet powder is transferred to a leaching vessel 14.

The leaching vessel 14 is generally a sealed container in which(NH₄)₂CO₃ and air (and/or O₂) is combined with the samarium cobaltmagnet powder to selectively dissolve the materials of the samariumcobalt magnet powder. For example, the samarium cobalt magnet maycomprise materials other than samarium cobalt, including iron, copper,nickel, etc. The leaching vessel 14 dissolves these materials with the(NH₄)₂CO₃ and air/O₂ and transfers the solution to a filter 16. Ironand/or samarium are removed from the solution and come out as solids.The filtrate from filter 16 is transferred to an electrowinning cell 18comprising a cathode and an anode (not shown).

The electrowinning cell 18 performs an electrowinning (also called anelectroextraction) on the filtrate from the filter 16, which results inthe electrodeposition of metals, such as cobalt, copper, nickel, and thelike, from the filtrate on the cathode. In some embodiments, thiselectrodeposition may be a selective/repetitive process. For example,the anode may initiate with a relatively low voltage such that copperfrom the filtrate may be deposited on the cathode. Then, the anode andthe cathode may be removed such that the copper may be recovered. Theanode and the cathode may then operate on the filtrate by applying ahigher voltage on the anode to extract cobalt from the filtrate on thecathode. This process may repeat until all of the desired metals hadbeen recovered from the filtrate.

FIG. 2 is a flowchart of an exemplary process 50 of the system 10 ofFIG. 1. In this embodiment, a permanent magnet material is converted toa higher surface area form, such as a powder, in the process element 52.For example, the milling/grinding module 12 may grind a samarium cobaltmagnet feed into a powder. Then, the feed may be treated with an aqueoussolution of ammonium carbonate to form a mixture that includes thedissolved cobalt, in the process element 54. For example, (NH₄)₂CO₃ andair/O₂ may be added to a sealed leaching vessel 14 to selectivelydissolve the metals within the powder. Then, the filter 16 may filterthe mixture to yield a filtrate, in the process element 56. In thisregard, iron may be filtered out of the mixture and output from thesystem 10 as iron solids. The remaining portion of the mixture may thenbe transferred to the electrowinning cell 18 such that the cobalt in thefiltrate may be electroplated onto a cathode, in the process element 58.Again, other metals may be selectively recovered in this electroplatingstep via the adjustment of voltage and/or amperage in the electroplatingprocess.

Based on the foregoing, the system 10 is any device, system, software,or combination thereof operable to convert a samarium cobalt permanentmagnet into a higher surface area form such that cobalt and/or othermetals may be extracted for reuse. Other exemplary embodiments are shownand described below.

While this embodiment illustrates one exemplary process for extractingcobalt from a permanent magnet material feed, the embodiments may alsobe operable to extract other metals, such as iron, copper, nickel, etc.from the permanent magnet material feed. In some embodiments, the system10 may be operable to extract cobalt from various forms of ore materialsthat have been mined and/or are a result of manufacturing waste.Additionally, the processing and extraction of the materials describedherein are not intended to be limited to materials mined or manufacturedon earth. Rather, the materials described herein may be extracted fromore material mined from various planets, moons, asteroids, and the like.

Experimental

Although the following exemplary experimental procedures are describedin detail, they are illustrative and non-limiting. Two differentstarting magnet materials were used for the research. Samarium cobaltdisc magnets (⅜″ diameter×⅛″ thick, SMCO-D5) were used and crushed in ahydraulic press prior to use. This resulted in a collection of magneticparticles which were used without further preparation. Alternatepreparation methods and demagnetization were investigated and will bedescribed where appropriate. Samarium cobalt cutting swarf submerged inan impure aqueous fluid was received as a smooth powder/paste from amanufacturer. 110.0 g of the wet swarf was filtered, washed withdistilled water (400 mL), and allowed to dry in a Buchner funnel undervacuum filtration. The mass of solid remaining was 82.6 g or 75.1%. Thispartially dried sample was then placed in a ceramic dish and heated to120° C. in a furnace for 2 hours. After cooling to room temperature, thefinal mass was 70.8 g. This material was used in leaching experimentswithout further processing. In some experiments, oxidized magnetmaterial was used instead of the alloys. In this case, the material washeated to 850° C. in a muffle furnace for 8 hours (ramp rate: 10°C./min) prior to use. The sintered material was then lightly groundusing a glass mortar and pestle to further break up any agglomeratedparticles. X-ray fluorescence (XRF) analysis was performed at PioneerAstronautics using a Rigaku NEX-DE Energy-Dispersive XRF spectrometerwith a silicon photodetector and a 60 kV sealed-tube source. Afundamental parameters measurement method was used for all samples. Asthis measurement is sensitive to elements from Na—U, all XRF results aregiven as mass % of a specific element out of the total mass of alldetectable elements. So, even if the metals were most likely present asoxides, the analytical results will give relative amounts of one metalto another. Powder samples were placed in polypropylene sample cups ormicrosample cups and tamped by hand to create a packed powder. Liquidsamples were analyzed by adding 4 g to a sample cup and running amanufacturer-installed method.

Experiment 1: General

1 gram (2.5 g/L) of crushed magnets was added to a 500 mL round-bottomflask along with a magnetic stir bar and 400 mL of 1.6 molar (NH₄)₂CO₃.Some of the magnet powder was attracted to the stir bar, but whilestirring vigorously, the liquid became cloudy and it was clear that asuspension was obtained. The suspension was stirred for 3 days at roomtemperature and left open to ambient air during which it turned a darkpurple hue. Upon filtering the suspension, a purple solution and a brownsolid fraction were obtained with the solid fraction composed primarilyof iron and samarium. The purple solution was heated at 120° C. toevaporate water and decompose ammonium carbonate into ammonia, carbondioxide, and water which then were evolved as gasses. The remainingsolids were composed of 83% cobalt and yielded a mass of cobaltequivalent to 100% of the initial cobalt in the magnets.

Experiment 2: Recycled Leach Solution

1 gram of crushed magnets was leached as outlined in Experiment 1, butthe process was performed in a nitrogen atmosphere instead of being opento air. The solids collected at the end of the experiment were composedof 87% cobalt and yielded a mass of cobalt equivalent to 18% of theinitial cobalt in the magnets.

Experiment 3:

40 mL of the filtrate obtained from Experiment 1 were added to a 50 mLbeaker and a nickel plate anode and a carbon plate cathode were placedin the solution and separated by a distance of one inch. A controlledpotential of 2.5 V was applied across the electrodes while the solutionwas magnetically stirred for two hours. Afterward, the cathode wasremoved and found to have plated a copper-colored solid with a mass of23 mg and was found to be composed of 80% copper, 18.4% cobalt, and 0.6%iron via XRF analysis. A new, identical cathode was placed in thesolution, electrically connected as before, and a controlled current of300 mA was passed while the voltage was allowed to float. After 40minutes, the cathode was removed, rinsed with distilled water, andallowed to dry. The cathode was found to have a dark coating with a massof 82 mg and was found to be composed of 93.3% cobalt, 4.3% nickel, 1.1%iron, and 0.8% copper. The remaining solution was found to have a pH of9.4, largely unchanged from the starting value of 9.2.

Experiment 4:

2 g (5 g/L) of samarium cobalt magnet swarf was added to a 500 mLround-bottom flask along with a magnetic stir bar and 400 mL of 1.6molar (NH₄)₂CO₃. Some of the magnet powder was attracted to the stirbar, but while stirring vigorously, the liquid became cloudy, and it wasclear that a suspension was obtained. The suspension was stirred for 48hours at room temperature and left open to ambient air during which itturned a dark purple hue. Upon filtering the suspension, a purplesolution and a brown solid fraction were obtained. The solids were foundto be composed of 48.0% iron, 41.1% samarium, 8.8% cobalt, and 1.4%zirconium, likely as either oxides or carbonates. The purple solutionwas analyzed and found to contain dissolved metals as 85% cobalt, 8%copper, 3% zirconium, 2% iron, and 2% samarium.

Experiment 5:

A hydrothermal experiment was conducted in a 50 mL autoclave reactorwith a PTFE liner and a pressure limit of 870 psia. 15 mL of distilledwater, 10 mL of 34% hydrogen peroxide solution, and 5 g of ammoniumcarbonate were added to the autoclave reactor along with 1 g of crushedsamarium cobalt magnets. The sealed reactor was then placed into amuffle furnace and heated to 130° C. at a rate of 10° C./min and held atthat temperature for 16 hours, resulting in an estimated pressure insidethe vessel of greater than 300 psia. The reactor was then allowed tocool to room temperature prior to opening the reactor. Upon opening, thereactor contents were filtered, and the filtrate was completelyevaporated at 120° C. to isolate the dissolved solids as a residue. Thisresidue was calcined at 850° C. for eight hours and washed withdistilled water to remove soluble salts prior to analysis using ScanningElectron Microscopy/Energy Dispersive X-Ray Spectroscopy (SEM/EDS) by acommercial analytical lab. 13 percent of the initial cobalt wasrecovered in the final product which was 81% cobalt. The concentrationof dissolved solids was estimated as 13 g/L, far in excess of what wasobtained in the alternate approaches described above.

Any of the above embodiments herein may be rearranged and/or combinedwith other embodiments. Accordingly, the concepts herein are not to belimited to any particular embodiment disclosed herein. Additionally, theembodiments can take the form of entirely hardware or comprising bothhardware and software elements. Portions of the embodiments may beimplemented in software, which includes but is not limited to firmware,resident software, microcode, etc. For example, software may be used tocontrol various reactions, processes, and hardware (e.g., pumps,reactors, condensers, etc.) presented herein. FIG. 3 illustrates oneexemplary computing system 500 in which a computer readable medium 506may provide instructions for performing any of the methods disclosedherein.

Furthermore, the embodiments can take the form of a computer programproduct accessible from the computer readable medium 506 providingprogram code for use by or in connection with a computer or anyinstruction execution system. For the purposes of this description, thecomputer readable medium 506 can be any apparatus that can tangiblystore the program for use by or in connection with the instructionexecution system, apparatus, or device, including the computer system500.

The medium 506 can be any tangible electronic, magnetic, optical,electromagnetic, infrared, or semiconductor system (or apparatus ordevice). Examples of a computer readable medium 506 include asemiconductor or solid state memory, magnetic tape, a removable computerdiskette, a random access memory (RAM), NAND flash memory, a read-onlymemory (ROM), a rigid magnetic disk and an optical disk. Some examplesof optical disks include compact disk—read only memory (CD-ROM), compactdisk—read/write (CD-R/W) and digital versatile disc (DVD).

The computing system 500, suitable for storing and/or executing programcode, can include one or more processors 502 coupled directly orindirectly to memory 508 through a system bus 510. The memory 508 caninclude local memory employed during actual execution of the programcode, bulk storage, and cache memories which provide temporary storageof at least some program code in order to reduce the number of timescode is retrieved from bulk storage during execution. Input/output orI/O devices 504 (including but not limited to keyboards, displays,pointing devices, etc.) can be coupled to the system either directly orthrough intervening I/O controllers. Network adapters may also becoupled to the system to enable the computing system 500 to becomecoupled to other data processing systems, such as through host systemsinterfaces 512, or remote printers or storage devices throughintervening private or public networks. Modems, cable modem and Ethernetcards are just a few of the currently available types of networkadapters.

VARIOUS EMBODIMENTS

In one embodiment, a Cobalt Extraction and Recycling from PermanentMagnets (CERPM) process recovers cobalt and other valuable metalelements from samarium cobalt magnets.

In one embodiment, the CERPM process recovers cobalt and other valuablemetal elements from partially or fully oxidized samarium cobalt magnets.

In one embodiment, the CERPM process recovers copper as a co-product.

In one embodiment, the CERPM process recovers nickel as a co-product.

In one embodiment the CERPM process recovers cobalt, copper, or nickelfrom manufacturing wastes such as cutting swarf in which oxidation ofthe alloy may have occurred.

In one embodiment the CERPM process recovers cobalt and other valuablemetal elements as high-quality feed stock to support manufacture of newhigh-performance magnets. The product metals may be combined with freshmaterial in any proportion to alter or enhance the magnetic properties.

In one embodiment, the cobalt metal product may be used as ahigh-quality feed stock for battery production.

In one embodiment, the cobalt metal product may be sold as a commodityto manufacturers or end-users.

In one embodiment of the process, a mechanical crushing pre-treatment isused to increase the surface area and partially demagnetize the startingmaterial.

In one embodiment of the process, a hydraulic press is used to crush thestarting material.

In another embodiment, pretreatment may include further grinding ormilling of the brittle magnet material to open additional surface area.

In other embodiments, additional pretreatment may be applied to adjustthe oxidation state prior to extraction using chemical, electrical, orother oxidation or reduction methods.

In one embodiment of the process, pretreatment of magnet powders byexposure to air at temperatures up to 1500° C. to oxidize magnet powderprior to extraction.

In one embodiment of the process, pretreatment of magnet powders heatingin an oxygen-free atmosphere above the Curie temperature to demagnetizemagnet powder prior to extraction. This may be up to 1500° C. fortypical applications, or higher for specific feeds.

In one embodiment of the process, pretreatment of magnet powders byexposure to hydrogen at temperatures up to 1500° C. to reduce cobalt andother oxides to metal prior to extraction.

In one embodiment of the process, pretreatment of magnets by exposure tohydrogen at high temperature or pressure to decompose the phases toelemental or hydride forms.

In one embodiment of the process, pretreatment may includedemagnetization of the magnetic starting material using an externallyapplied magnetic field or a shock treatment.

In one embodiment, a recoverable aqueous ammonium carbonate leachsolution is used to decompose permanent magnet alloy compositions at lowtemperature and pressure into insoluble precipitates and soluble metalcomplexes.

In one embodiment, the leach solution is composed of 1.6 molar ammoniumcarbonate.

In other embodiments, the leach solution is composed of ammonia andammonium carbonate in any proportion from 0.1 molar to saturated.

In one embodiment, after selective recovery of constituents from themixture, the extraction solution is directly recycled.

In another embodiment, the extraction solution is heated to releaseammonia and carbon dioxide, which are recovered and then recycled to theprocess.

In one embodiment, oxygen gas is used as an oxidant in the leachingstep.

In one embodiment, air is used as an oxidant in the leaching step.

In one embodiment, a chemical oxidant such as hydrogen peroxide is usedas an oxidant in the leaching step.

In one embodiment, an inert atmosphere is used in the leaching step.

In one embodiment, hydrogen gas or another chemical reductant is used inthe leaching step.

In one embodiment, the extraction process is typically carried out atambient temperature.

In one embodiment, the extraction process is typically carried out attemperatures between ambient and 60° C.

In one embodiment, the extraction process is typically carried out attemperatures above 60° C. and at pressure greater than 1 atmosphere.

In one embodiment, the extraction process is typically carried out attemperatures above 100° C. and at pressure greater than 1 atmosphere.

In one embodiment, the extraction process is typically carried out invessels constructed of stainless-steel without any lining.

In one embodiment, the extraction process is typically carried out invessels composed of or lined with glass.

In one embodiment, the extraction process is typically carried out invessels composed of or lined with polytetrafluoroethylene (PTFE).

In other embodiments, the extraction process is typically carried out invessels composed of or lined with a corrosion barrier that does notreact with the mixture.

In one embodiment of the process, CO₂ is added to the filtrate toprecipitate some of the dissolved compounds prior to further processing.

In one embodiment of the process, addition of a base to the filtratecauses precipitation of dissolved cobalt.

In one embodiment of the process, addition of an acid to the filtratecauses precipitation of dissolved cobalt.

In one embodiment of the process, addition of either an acid or a baseto the filtrate causes precipitation of dissolved iron or another basemetal.

In one embodiment of the process, CO₂, air, oxygen, hydrogen peroxide,etc. is used to change the Eh of the filtrate and cause precipitation ofthe cobalt or dissolved iron.

In one embodiment of the process, heat, steam, or evaporation isemployed to cause precipitation of dissolved compounds from thefiltrate.

In one embodiment of the process, a reagent such as a sulfur compound isadded to the filtrate to form an insoluble cobalt species.

In one embodiment, the electrochemical reactor consists of twoelectrodes in a single chamber.

In another embodiment, the electrochemical reactor consists of twoelectrodes in two separate chambers.

In another embodiment, the electrochemical reactor consists of twoelectrodes separated by a membrane which allows some but not allcomponents to pass through.

In another embodiment, a third or fourth electrode is used as areference electrode.

In one embodiment, the potential is held constant throughout theelectrowinning step.

In another embodiment, the current passed is held constant throughoutthe electrowinning step.

In another embodiment, the potential or current are varied or sweptfollowing a programmed pattern throughout the electrowinning step.

In one embodiment, the anode is composed of nickel and the cathode iscomposed of carbon.

In other embodiments, the anode or cathode may be composed of anyconductive material.

In another embodiment, the anode or cathode may be prepared orstructured to increase the surface area, increase the rate of thedesired reaction, or limit the rate of undesired reactions.

In another embodiment, additional chemicals may be added to the solutionto improve the quality of the plating.

In another embodiment, additional chemicals may be added to improve thereaction kinetics of oxygen evolution at the anode.

In another embodiment, additional chemicals are added to slow thehydrogen evolution reaction at the cathode.

In one embodiment, copper metal or another coproduct is plated prior toplating cobalt.

In another embodiment, copper, cobalt, and/or other dissolved metalcompounds are co-plated on an electrode.

In one embodiment of the process, direct recycle of ammonium carbonateand/or ammonia is done after precipitation of solids.

In one embodiment of the process, multiple extraction stages areemployed to further separate cobalt from iron or other contaminants.

In one embodiment of the process, additives for leaching orprecipitation are recovered and reused.

In one embodiment, the solution is heated after electrowinning cobalt toevolve ammonia and carbon dioxide for capture and reuse.

In one embodiment of the process, the process feed is obtained from anasteroid, the moon, Mars, or other extraterrestrial resources.

In situ resource utilization (ISRU) may be generally defined as thecollection, processing, storing and use of materials encountered in thecourse of human or robotic terrestrial or space exploration that replacematerials that would otherwise be brought from a remote location such asanother geographic location or another planet or location in space.

In some embodiments, the process employs ISRU leveraging resources foundor manufactured on other astronomical objects (the Moon, Mars,asteroids, etc.) to fulfill or enhance the requirements and capabilitiesof a space or terrestrial mission.

In other embodiments, the process is useful in recovering cobalt,rare-earth, and/or precious metals from an asteroid and otherextra-terrestrial site such as planet Mars or the moon.

In one embodiment, the process is used in asteroid mining to recovervaluable cobalt, rare-earth metals, and precious metals.

What is claimed is:
 1. A method of recovering cobalt from a permanentmagnet material having variable composition, the method comprising:converting the permanent magnet material to a higher surface area form;treating the converted permanent magnet material with an aqueoussolution of ammonium carbonate to form a mixture that includes dissolvedcobalt; filtering the mixture to yield a filtrate; and electroplatingthe cobalt onto a cathode from the filtrate.
 2. The method of claim 1,wherein: the permanent magnet material comprises samarium cobaltmagnets.
 3. The method of claim 1, wherein converting the permanentmagnet material to a higher surface area form comprises: at least one ofgrinding or milling the permanent magnet material.
 4. The method ofclaim 1, further comprising: heating the mixture in at least one of air,oxygen, an inert atmosphere, or hydrogen to temperatures up to 1500° C.5. The method of claim 1, further comprising: demagnetizing the mixtureusing an externally applied magnetic field or a mechanical shocktreatment.
 6. The method of claim 1, further comprising: adjusting anoxidation state of the mixture prior to extraction with a chemicaloxidant, a reductant, or an electrochemical method that employs anelectric current to transfer electrons between materials.
 7. The methodof claim 1, wherein: the aqueous solution of ammonium carbonatecomprises ammonium carbonate and ammonia.
 8. The method of claim 1,further comprising: recycling the aqueous solution of ammonium carbonateafter use.
 9. The method of claim 8, wherein recycling the aqueoussolution of ammonium carbonate after use comprises: thermally treatingthe aqueous solution of ammonium carbonate after use to convert the usedammonium carbonate solution into ammonia and carbon dioxide.
 10. Themethod of claim 1, wherein treating the converted permanent magnetmaterial with an aqueous solution of ammonium carbonate comprises:adding at least one of oxygen gas, air, hydrogen peroxide, a chemicaloxidant, hydrogen gas, or a chemical reductant.
 11. The method of claim1, further comprising: applying an electrical potential to a slurrycontaining alkaline carbonates and the permanent magnet material toincrease a dissolution rate.
 12. The method of claim 1, furthercomprising: heating the aqueous solution of ammonium carbonate to atemperature between 0° C. and 100° C. at a pressure above 1 bar.
 13. Themethod of claim 1, wherein: one or more of said converting, treating theconverted permanent magnet material, filtering, and treating thefiltrate are performed in a container constructed of at least one ofstainless steel, glass, polytetrafluoroethylene, fiberglass-reinforcedplastic, corrosion resistant alloy, or a corrosion barrier.
 14. Themethod of claim 1, further comprising: electroplating at least one ofcopper or nickel onto the cathode.
 15. The method of claim 1, furthercomprising: adding reagents to the mixture to slow hydrogen evolution atthe cathode or to increase a rate of oxygen evolution at an anode.